CN103611505A - Preparation method, product and application of copper ion functionalized porous cellulose composite microsphere - Google Patents

Abstract

The invention discloses a method for preparing porous cellulose composite microspheres functionalized by copper ions, as well as products and applications thereof. The preparation method is based on the combination of double emulsion-solvent removal method and ion cross-linking technology, including the following steps, firstly, the internal water phase W1 composed of an aqueous solution of carboxyl or amine functionalized hydrophilic polymer material and the organic compound of oil-soluble cellulose The oil phase O of the solution is emulsified to obtain a water-in-oil W1/O emulsion, and then the W1/O emulsion is added to the external water phase composed of a copper ion aqueous solution, and the organic solvent is removed by solvent evaporation or diffusion method, and ion exchange occurs. Copper ion-functionalized porous cellulose composite microspheres were prepared through the combined reaction. The copper ion-functionalized porous cellulose composite microspheres have a particle size in the range of 10.0-2000 microns, a pore volume of 0.5-8.0mL/g, a pore diameter of 20-12000nm, and a specific surface area of 1.0-60m ² /g. The content is 0.1-10.0%. Adding this material to cigarette filters can reduce the amount of hydrogen cyanide released in smoke by more than 25%.

Description

A preparation method of copper ion functionalized porous cellulose composite microspheres and its products and applications

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Technical field:

The invention belongs to the field of cigarette filter additives, and in particular relates to a preparation method of porous cellulose composite microspheres functionalized with copper ions and its product and application.

Background technique:

Hydrogen cyanide is one of the harmful components of cigarette smoke. The domestic and foreign research on reducing the release of hydrogen cyanide in cigarette smoke mainly includes catalytic oxidation and adsorption. Catalytic oxidation often uses noble metal catalysts, which require high production costs and complicated preparation processes. For example, Chinese patent 200410023246.7 supports Al2O3 or TiO2 with nano-gold to obtain a catalyst capable of reducing hydrogen cyanide in mainstream cigarette smoke. In the study of reducing the hydrogen cyanide release in flue gas by adsorption method, activated carbon is the most commonly used. For example, patent WO2007117115 utilizes the high specific surface area of activated carbon to effectively adsorb tar, HCN and other substances in flue gas. However, activated carbon as a filter rod additive often has a negative impact on the smoking taste of cigarettes, for example, the flavor saturation of cigarettes decreases. In view of the acidity of hydrogen cyanide and the high complexing ability of cyanide, basic materials and loaded transition metal-based materials are used in the research of reducing hydrogen cyanide in mainstream cigarette smoke. U.S. Patent No. 3,878,289 uses Al2O3 and SiO2 loaded with alkali metal hydroxides to achieve the purpose of reducing the amount of HCN released in cigarette smoke. Chinese patent 200910172250.2 obtains a modified porous material containing quaternary ammonium base groups by modifying the porous carrier, which can reduce hydrogen cyanide by more than 30%. In US2007/0295346, activated carbon impregnated with transition metals is added to the filter to reduce HCN in cigarette smoke. Chinese patent 201010542254.8 obtains complexed materials by complexing porous carriers with large specific surface areas, such as ion exchange resins, ion exchange fibers, and macroporous adsorption resins, etc., with different metal ions. Applied to cigarettes, it can selectively reduce HCN in the mainstream smoke of cigarettes by more than 25%. However, the above-mentioned materials all have a certain degree of disadvantages, such as the materials used are not environmentally friendly, the adsorption effect of hydrogen cyanide is not obvious enough, it affects the taste of cigarettes, the preparation process is complicated, and the cost is high, etc., and its application is limited.

Cellulose is the most abundant natural polymer material in nature. It is a renewable resource, biodegradable, and a class of environmentally and biologically friendly polymer materials. It is of great significance to prepare high-value products using cellulose and its derivatives as raw materials. Chinese patent 201210070945.1 uses cellulose as the base material, polymer material as the composite material, and alkali/urea aqueous solution or alkali/thiourea aqueous solution as the solvent to obtain cellulose composite microstructure through sol-gel transformation and crosslinking agent crosslinking. ball. Chinese patent 200610010145.5 dissolves cellulose, dyes and foaming agents in an aqueous solution composed of urea, thiourea, sodium hydroxide and additives; spins to form droplets and solidifies the droplets with an aqueous solution of inorganic acid to obtain porous fluffy colored fibers Prime particles. The above method or preparation process is relatively cumbersome, or the cellulose microspheres are tightly bound inside, and the adsorption capacity is not strong enough, which limits its application.

Invention content:

The object of the present invention is to provide a preparation method and application of copper ion functionalized porous cellulose composite microspheres based on the above-mentioned prior art.

The purpose of the present invention is achieved through the following technical solutions:

A preparation method of copper ion functionalized porous cellulose composite microspheres, the method is based on the combination of double emulsion-solvent removal method and ion cross-linking technology, comprising the following specific steps:

(1) The internal water phase W1 composed of an aqueous solution of a carboxyl or amine-functionalized hydrophilic polymer material is added to the oil phase O composed of an oil-soluble cellulose organic solution for emulsification to obtain a water-in-oil W1/O emulsion ;

(2) Add the W1/O emulsion to the external water phase W2 composed of copper ion aqueous solution to obtain a W1/O/W2 double emulsion. The organic solvent is removed by solvent volatilization or diffusion method, and the droplets are solidified. During the solidification process of the droplets, the external The copper ions in the water phase W2 undergo an ionic cross-linking reaction with the hydrophilic polymer material in the inner water phase W1 and are compounded in the microspheres. After filtering, washing and drying, the porous cellulose composite microspheres functionalized with copper ions are obtained. .

The hydrophilic polymer material functionalized with carboxyl or amino groups is a kind of carboxymethyl cellulose, carboxymethyl starch, carboxymethyl chitosan, chitosan, carboxymethyl cyclodextrin, polyacrylic acid or more, and its concentration in the internal water phase W1 is 0.5-5.0 wt%.

The method for preparing porous cellulose composite microspheres functionalized with copper ions is characterized in that the concentration of copper ions in the external water phase W2 is 0.01-0.5 mol/L.

The oil-soluble cellulose is cellulose acetate, ethyl cellulose or a mixture of the two, and its concentration in the oil phase O is 1.0-10.0 wt%.

The oil phase solvent is one of ethyl acetate, methyl acetate, dichloromethane, chloroform or a mixture of any two.

The mass ratio of the inner water phase, the oil phase and the outer water phase is 0.05-1.3: 1: 2-20.

When preparing W1/O emulsion and W1/O/W2 emulsion, add emulsifiers such as polyvinyl alcohol, sodium lauryl sulfate, sucrose ester, Tween-80, Span-20 or Span-80 as needed , The amount of emulsifier added is 0.2-2.0%. The emulsifier can be added to the inner water phase, oil phase or outer water phase.

The copper ion-functionalized porous cellulose composite microspheres prepared by the above method are composed of cellulose acetate or ethyl cellulose and copper ion cross-linked hydrophilic polymers, and the particle size of the microspheres is 10 In the range of ～2000 microns, scanning electron microscopy shows that the microspheres have an interconnected pore structure. Mercury porosimetry test shows that the pore volume of the microspheres is 0.5～8.0 mL/g, and the pore diameter is 20～12000 nm. The nitrogen adsorption measurement shows that the BET ratio of the microspheres is The surface area is 1-60 m ² /g, and the copper ion content of the microspheres is 0.1-10.0 wt% as determined by ICP-MS.

Adding porous cellulose composite microspheres to cigarette filters as composite filter additive particles can reduce the release of hydrogen cyanide in mainstream smoke by more than 25%.

The copper ion-functionalized porous cellulose composite microspheres provided by the present invention reduce the release of hydrogen cyanide in smoke mainly based on the complexation of hydrogen cyanide and copper ions. The interconnected pore structure of the microspheres ensures that the smoke Fast transmission and effective contact area.

The beneficial effects of the present invention are: (1) copper ion cross-linked carboxymethyl cellulose, carboxymethyl starch, chitosan, carboxymethyl chitosan, carboxymethyl ring are dispersed inside the microsphere provided by the present invention Hydrophilic components such as dextrin, these components endow composite microspheres with various characteristics, for example, the introduction of copper ions improves the performance of composite microspheres in reducing hydrogen cyanide in smoke; the introduction of hydrophilic components not only The pore structure of the microsphere is enriched, and the microsphere can absorb moisture in the air, further improving its ability to reduce the harmful components of the smoke. (2) The base material of the microspheres is cellulose acetate or ethyl cellulose, and its chemical structure is similar to that of the existing cigarette filter material (fiber acetate is the main product currently on the market), and basically has no effect on the smoking taste of cigarettes.

Detailed ways:

The present invention will be further described below in conjunction with the examples, but the content of the present invention is not limited thereto.

Example 1

(1) Configuration of inner water phase, oil phase and outer water phase:

3.0 g carboxymethyl cellulose is dissolved in 97 g water to obtain inner water phase;

10.0g cellulose acetate was dissolved in 90.0g ethyl acetate to obtain an oil phase;

Dissolve 12.5 g of copper sulfate pentahydrate and 0.10 g of polyvinyl alcohol into 1000 g of water to obtain the external aqueous phase.

(2) Preparation of W1/O emulsion: Add 100g of internal water phase to 100g of oil phase, and use a high-speed emulsifier at 10000rpm to emulsify evenly to obtain W1/O emulsion;

(3) Preparation of microspheres: drop the above W1/O emulsion into 1000 g of the external water phase, keep the temperature at 50 ^o C, stir mechanically at a speed of 200 rpm, volatilize the solvent, solidify to obtain microspheres, wash and dry to obtain microspheres .

The average particle size of the microspheres is 210 microns, the BET specific surface area is 13.1 m ² /g, the copper content is 5.1%, the pore volume is 2.6mL/g, and the median pore diameter is 942nm.

Example 2

(1) Configuration of inner water phase, oil phase and outer water phase:

1.5g carboxymethyl cellulose is dissolved in 43.5 g water to obtain inner water phase;

5g ethylcellulose is dissolved in 95g methylene chloride to obtain an oily phase;

Dissolve 25g of copper sulfate pentahydrate and 0.20g of polyvinyl alcohol into 1000g of water to obtain the external aqueous phase.

(2) Preparation of W1/O emulsion: add 50g of internal water phase to 100g of oil phase, and use a high-speed emulsifier to emulsify evenly to obtain W1/O emulsion;

(3) Preparation of microspheres: drop the above W1/O emulsion into 1000 g of the external water phase, keep the temperature at 30 ^o C, stir mechanically at a speed of 300 rpm, volatilize the solvent, solidify to obtain microspheres, wash and dry to obtain microspheres.

The average particle size of the microspheres is 300 microns, the BET specific surface area is 5.2 m ² /g, the copper content is 3.7%, the pore volume is 1.9 mL/g, and the median pore diameter is 2250 nm.

Example 3

(1) Configuration of inner water phase, oil phase and outer water phase:

2g carboxymethyl starch is dissolved in 48g water to obtain inner water phase;

5g ethylcellulose is dissolved in 95g methylene chloride to obtain an oily phase;

12.5g copper sulfate pentahydrate, 0.20g polyvinyl alcohol are dissolved in 1000g water to obtain the outer water phase. 

(2) Preparation of W1/O emulsion: add 20g of internal water phase to 100g of oil phase, and use a high-speed emulsifier to emulsify evenly to obtain W1/O emulsion;

(3) Preparation of microspheres: drop the above W1/O emulsion into 1000 g of the external water phase, stir mechanically at a speed of 300 rpm, evaporate the solvent at room temperature, solidify to obtain microspheres, wash and dry to obtain microspheres.

The average particle size of the microspheres is 160 microns, the BET specific surface area is 4.1 m ² /g, the copper content is 2.9%, the pore volume is 2.2 mL/g, and the median pore diameter is 980 nm.

Example 4

(1) Configuration of inner water phase, oil phase and outer water phase:

1.5g carboxymethyl chitosan is dissolved in 48.5g water to obtain inner water phase;

5g ethylcellulose is dissolved in 95g methylene chloride to obtain an oily phase;

12.5g of copper sulfate pentahydrate and 0.20g of polyvinyl alcohol were dissolved in 1000g of water to obtain an external aqueous phase.

(2) Preparation of W1/O emulsion: add 50g of internal water phase to 100g of oil phase, and use a high-speed emulsifier to emulsify evenly to obtain W1/O emulsion;

(3) Preparation of microspheres: drop the above W1/O emulsion into 1000 g of the external water phase, stir mechanically at a speed of 300 rpm, evaporate the solvent at room temperature, solidify to obtain microspheres, wash and dry to obtain microspheres.

The average particle diameter of the microspheres is 160 microns, the BET specific surface area is 17 m ² /g, the pore volume is 6.5 mL/g, and the median pore diameter is 1040 nm.

Example 5

(1) Configuration of inner water phase, oil phase and outer water phase:  

10g of carboxymethyl-β-cyclodextrin was dissolved in 90g of water to obtain the inner water phase;

5g cellulose acetate is dissolved in 95g ethyl acetate to obtain the oil phase;

12.5g copper sulfate pentahydrate, 0.20g polyvinyl alcohol are dissolved in 1000g water to obtain the outer water phase. 

(2) Preparation of W1/O emulsion: add 80 g of internal water phase to 100 g of oil phase, and use a high-speed emulsifier to emulsify evenly to obtain W1/O emulsion;

(3) Preparation of microspheres: drop the above W1/O emulsion into 1000 g of the external water phase, stir mechanically at a speed of 100 rpm, evaporate the solvent at room temperature, solidify to obtain microspheres, wash and dry to obtain microspheres.

The average particle diameter of the microspheres is 360 microns, the BET specific surface area is 7.0 m ² /g, the pore volume is 4.8mL/g, and the median pore diameter is 320nm.

Example 6

(1) Configuration of inner water phase, oil phase and outer water phase:

8g carboxymethyl-β-cyclodextrin and 2g carboxymethylcellulose were dissolved in 90g water to obtain the inner water phase;

Dissolve 5g of ethyl cellulose and 2g of cellulose acetate in 93g of ethyl acetate/dichloromethane (mass ratio 1:1) mixed solvent to obtain an oil phase;

Dissolve 10.0 g cupric chloride and 0.20 g polyvinyl alcohol into 1000 g water to obtain the outer aqueous phase. 

(2) Preparation of W1/O emulsion: add 40 g of internal water phase to 100 g of oil phase, and use a high-speed emulsifier to emulsify evenly to obtain W1/O emulsion;

(3) Preparation of microspheres: drop the above W1/O emulsion into 300 g of the external water phase, stir mechanically at a speed of 300 rpm, evaporate the solvent at room temperature, solidify to obtain microspheres, wash and dry to obtain microspheres.

The average particle diameter of the microspheres is 360 microns, the BET specific surface area is 39 m ² /g, the pore volume is 7.8 mL/g, and the median pore diameter is 540 nm.

Example 7

The microspheres in Examples 1-3 are used as composite filter additive granules, the numbers are respectively 1#, 2# and 3#, and the amount of microspheres added is 15 mg/piece. Taking ordinary cigarettes as a control sample, smoke according to the standard Conditional re-smoking machine was used to carry out cigarette smoking experiment, and the content of HCN in the mainstream smoke was measured. The results are as follows:

Microsphere sample control 1# 2# 3# HCN contentug/cig 102.4 51.1 65.4 74.4 HCN reduction rate - 50.1% 36.1% 27.3%

Claims (8)

1. a preparation method of copper ion functionalized porous cellulose composite microspheres, characterized in that: the method is based on the combination of double emulsion-solvent removal method and ion cross-linking technology, comprising the following specific steps: (1) The internal water phase W1 composed of an aqueous solution of a hydrophilic polymer material functionalized with carboxyl or amine groups is added to the oil phase O composed of an oil-soluble cellulose organic solution to emulsify to obtain a water-in-oil W1/O emulsion; (2) Add the W1/O emulsion to the external water phase W2 composed of copper ion aqueous solution to obtain a W1/O/W2 double emulsion. The organic solvent is removed by solvent volatilization or diffusion method, and the droplets are solidified. During the solidification process of the droplets, the external The copper ions in the water phase W2 undergo an ionic cross-linking reaction with the hydrophilic polymer material in the inner water phase W1 and are compounded in the microspheres. After filtering, washing and drying, the porous cellulose composite microspheres functionalized with copper ions are obtained. . 2. according to the preparation method of the porous cellulose composite microsphere of copper ion functionalization described in claim 1, it is characterized in that: the hydrophilic macromolecule material of described carboxyl or amino functionalization is carboxymethyl cellulose, carboxyl One or more of methyl starch, carboxymethyl chitosan, chitosan, carboxymethyl cyclodextrin and polyacrylic acid, the concentration of which in the internal aqueous phase W1 is 0.5-5.0 wt%. 3. The method for preparing porous cellulose composite microspheres functionalized with copper ions according to claim 1, characterized in that: the concentration of copper ions in the external water phase W2 is 0.01-0.5 mol/L. 4. according to the preparation method of the porous cellulose composite microsphere of copper ion functionalization described in claim 1, it is characterized in that: described oil-soluble cellulose is cellulose acetate, ethyl cellulose or the mixture of both, and it is in The concentration of O in the oil phase is 1.0-10.0 wt%. 5. according to the preparation method of the described copper ion functionalized porous cellulose composite microsphere of claim 1, it is characterized in that: described oil phase solvent is ethyl acetate, methyl acetate, dichloromethane, trichloromethane One or a mixture of any two. 6. The preparation method of the porous cellulose composite microsphere functionalized with copper ions according to claim 1, characterized in that: the mass ratio of the inner water phase, the oil phase, and the outer water phase is 0.05～1.3 : 1 : 2 ~20. 7. A porous cellulose composite microsphere of copper ion functionalization prepared by the method of claim 1, characterized in that: the composite microsphere is highly hydrophilic by cellulose acetate or ethyl cellulose and copper ion crosslinking Molecular composition, microspheres have interconnected pore structure, the particle size is in the range of 10-2000 microns, the pore volume is 0.5-8.0 mL/g, the pore diameter is 20-12000 nm, the BET specific surface area is 1.0-60 m ² /g, the microsphere The copper ion content in the ball is 0.1-10.0 wt%. 8. an application of the copper ion functionalized porous cellulose composite microsphere prepared by the method of claim 1, characterized in that: the porous cellulose composite microsphere is added in the cigarette filter as the composite filter tip additive particle, which can Reduce the release of hydrogen cyanide in mainstream smoke by more than 25%.